If you have seen the movie The Sound of Music, you may think you know all there is to see in Salzburg.

Admittedly, it is difficult not to burst into song when you're walking along the Salzach River, or climbing up to the Hohensalzburg fortress which looms over the city. Prostitution is legal but restricted by several regulations.

Vienna recently celebrated the 150th birthday of Gustav Klimt.

A pioneer of the Modernist painting style, Klimt spent most of his life in Vienna and is best known for , currently on display at the Belvedere.

In Vienna, prostitution with hundreds of brothels and massage parlors is a booming business.

Only famous sex destinations like Amsterdam and Hamburg can rival Vienna's reputation of a particularly sinful city for sex travelers.

In Vienna the figures are almost the same; 38 percent of the registered prostitutes in Vienna came from Romania, 26 percent from Hungary, and 10 percent from Bulgaria.